CN102608566A - Anchor node optimal configuration method based on ultra-wideband asynchronous positioning - Google Patents

Abstract

The invention relates to an anchor node optimal configuration method based on ultra-wideband asynchronous positioning. The method comprises the following step of arranging anchor nodes in optimal positions, so that higher performance can be obtained by utilizing a small number of anchor nodes and the compromise between the performance and energy consumption can be further achieved; and if the anchor nodes are arranged in bad positions, the performance gain obtained by increasing the anchor nodes can be offset, so that the performance obtained by a large number of anchor nodes is poorer than that obtained by a small number of anchor nodes. Regions in different sizes have different optimal schemes, and a relation between the two is further given out. When the affects of path loss on a range error are considered, one optimal scheme exists, and if the anchor nodes are arranged in the position, the optimal average performance can be obtained.

Description

Anchor node based on the asynchronous location of ultra broadband is distributed method rationally

Technical field

The present invention relates to a kind of anchor node and distribute method rationally, relate in particular to a kind of anchor node and distribute method rationally based on the asynchronous location of ultra broadband.

Background technology

In based on the ultra broadband position fixing process, the configuration of anchor node is very big to the influence of positioning result, be without loss of generality, and be example with the two dimensional surface, three dimensions is similar.At present, it is generally acknowledged that M anchor node is optimum geometry when being distributed on the summit of positive M limit shape, and the midpoint of target shape on positive M limit can obtain best bearing accuracy.But there is following problem in the existing anchor node technology of distributing rationally: (1) target might appear at the optional position in the zone, and therefore only the optimum position of research has little significance.(2) not considering the influence of path loss to the range finding result, promptly all is that the hypothesis range error is irrelevant with path loss.More abominable when environment, when path loss had a strong impact on range error, such hypothesis was irrational.

Summary of the invention

The technical matters that the present invention solves is: make up a kind of anchor node based on the asynchronous location of ultra broadband and distribute method rationally, overcome the to be measured destination node of prior art for some position in the zone, the technical matters of bearing accuracy difference.

Technical scheme of the present invention is: make up a kind of anchor node based on the asynchronous location of ultra broadband and distribute method rationally; Clock is asynchronous between said a plurality of anchor node, and the anchor node method of distributing rationally is: said a plurality of destination nodes to be measured evenly distribute, and said a plurality of anchor nodes are distributed on the summit of regular polygon; Satisfy apart from r to anchor node at the center of said destination node to be measured distributed areas: r=aR+b; Wherein, a, b are coefficient, and R is the radius of destination node to be measured distributed areas.

Further technical scheme of the present invention is: also comprise and consider the influence of path loss to range error, set path dissipation factor.

Further technical scheme of the present invention is: also comprise and consider the influence of path loss to range error, set the standard deviation of range error.

Further technical scheme of the present invention is: comprise and obtain the average behavior that is evenly distributed on the destination node to be measured in the zone.

Further technical scheme of the present invention is: adopt least square method that regional center is carried out mathematical modeling to anchor node apart from r.

Technique effect of the present invention is: the anchor node that the present invention is based on the asynchronous location of ultra broadband is distributed method rationally; Clock is asynchronous between said a plurality of anchor node, and the anchor node method of distributing rationally is: said a plurality of destination nodes to be measured evenly distribute, and said a plurality of anchor nodes are distributed on the summit of regular polygon; Satisfy apart from r to anchor node at the center of said destination node to be measured distributed areas: r=aR+b; Wherein, a, b are coefficient, and R is the radius of destination node to be measured distributed areas.The anchor node that the present invention is based on the asynchronous location of ultra broadband is distributed method rationally, anchor node is arranged in optimal location can utilizes a spot of anchor node to obtain higher performance, thereby reach the compromise of performance and energy consumption; And if anchor node has been arranged in bad position, then can be cancelled the performance that the performance that a large amount of anchor nodes are obtained obtains not as a small amount of anchor node through increasing the performance gain that anchor node obtains.There is different optimum r in the zone of different sizes, provides the relation of the two.When considering path loss to the influencing of range error, there is an optimum r, if anchor node is arranged in this position, can obtain the average behavior of optimum.

Description of drawings

Fig. 1 is the present invention's destination node distribution schematic diagram to be measured.

The topology diagram that Fig. 2 distributes for anchor node of the present invention.

Fig. 3 is the average behavior of the present invention's destination node to be measured and the graph of a relation of r and anchor node number.

Fig. 4 is the average behavior of the present invention's destination node to be measured and the graph of a relation of r and zone radius.

Fig. 5 is the graph of a relation of optimum r of the present invention and R.

Embodiment

Below in conjunction with specific embodiment, technical scheme of the present invention is further specified.

Like Fig. 1, Fig. 2, shown in Figure 5, embodiment of the present invention is: make up a kind of anchor node based on the asynchronous location of ultra broadband and distribute method rationally, clock is asynchronous between said a plurality of anchor nodes; The anchor node method of distributing rationally is: said a plurality of destination nodes to be measured evenly distribute; Said a plurality of anchor node is distributed on the summit of regular polygon, and said regional center satisfies apart from r to anchor node: r=aR+b, wherein; A, b are coefficient, and R is the radius of destination node to be measured distributed areas.

Like Fig. 1, Fig. 2, shown in Figure 5; Practical implementation process of the present invention is following: in the specific embodiment; The equally distributed area format of said a plurality of destination nodes to be measured is not limit, and calculates for convenient, and a plurality of destination nodes to be measured described here are evenly distributed in the circle that radius is R; The centre coordinate of circle is (0,0).R does not wait from 4 meters to 7 meters, promptly typical WPAN (Wireless Personal Network) scope.In estimation theory, the variance that any nothing is partially estimated all has a lower limit, and among the present invention, this does not have estimates to be exactly the positioning result of destination node to be measured partially, and the lower limit minimum value that to be exactly the variance of positioning result error can reach, just CRLB.The CRLB bright performance of novel more is good more.In the method; Because destination node to be measured is equally distributed at random; Therefore study average positioning performance; Just the computing method of average CRLB

average behavior

are that the performance addition of all destination nodes to be measured is made even all then, as shown in the formula:

$\stackrel{\‾}{\mathrm{CRLB}}=\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{CRLB}\left(i\right)}{N}---\left(1\right)$

In the formula (1), CRLB (i) represents the performance of i destination node to be measured, and N representes the number of destination node to be measured.

Consider the influence of path loss to range error, and hypothesis path loss factor-alpha=4, the standard deviation of range error is σ ₀=0.02m.

" statistical signal is handled the basis---estimate and etection theory " (Beijing: Electronic Industry Press; 2006.7 [U.S.A] Steven M.Kay work Luo Peng flies the gorgeous grade of Zhang Wenming Zhao Liu Zhong and translates) in the book; The 39th page of explanation relevant for the anchor node performance CRLB of general Gauss's situation supposed

x：N(μ(θ)，C(θ))(2)

For formula (2), in the patent art scheme, x representes that signal in the position fixing process arrives the estimated value of the range difference of destination node to be measured from different anchor nodes, and μ (θ) is the actual value of range difference, and C (θ) is the variance of estimated value error.X is the vector form of Gauss measurement value, and its average maybe be all relevant with θ with variance.The derivation of CRLB is provided by 62 pages appendix 3C.

As shown in Figure 2, the geometry that anchor node distributes is a mode of thinking optimum at present, and promptly M anchor node is distributed on the summit of positive M limit shape, the distance at each anchor node distance areas center all be r (r≤R), then the coordinate of anchor node i is:

$\begin{array}{c}{x}_i=\mathrm{<figure-callout\; id="2"\; label="r\; cos"\; filenames="120111104429.png,120111104435.png"\; state="\{\{state\}\}">r</figure-callout>}\cos \frac{2\mathrm{\&pi;}(i-1)}{M},y_i=r\sin \frac{2\mathrm{\&pi;}(i-1)}{M}\\ i=\mathrm{1,2},...,M\end{array}---\left(3\right)$

Through type (3); Just can the coordinate (position of anchor node just) of anchor node be connected with r, to distributing rationally of anchor node, just only need discuss to r gets final product; Because there is definite relation the position of r and anchor node, therefore there has been r that the position of anchor node has also just been arranged.

As can be seen from Figure 3; Under the certain situation in zone (R=5m here), no matter how many numbers of anchor node is (different curves are represented different anchor node number M=5,6 among the figure; 7; 8), all there is one and makes

minimum r, just optimum r.As can be seen from Figure 3, increase the anchor node number and can improve positioning performance, this is the common recognition of all positioning systems; Be a kind of means that improve performance; But the increase of anchor node number means the increase of energy consumption simultaneously, thereby influences network life, so this is not a kind of good method.And, have the another kind of means that improve performance based on asynchronous time of arrival of poor localization method, and that is arranged in rational position with anchor node exactly, can utilize less anchor node to obtain higher performance, thus the compromise of the performance of obtaining and energy consumption.Such as, obtain-2.6 (dBm ²) performance, if r=1.6m then only need 6 anchor nodes, and if r=1m or r=3.4m would then need 7 and 8 anchor nodes respectively.For another example, if 8 anchor nodes are placed on the r=5m place, the performance that then obtains will be worse than 5 anchor nodes are placed on the r=1.6m place.That is to say that irrational anchor node position can balance out the performance gain that the increase anchor node brings.

As shown in Figure 4, zone radius R variation from 4 meters to 7 meters, the optimum r of anchor node number M=6. changes along with the variation of R, obeys linear relationship between the two.Utilize least square fitting that optimum r is carried out mathematical modeling below.

Can obtain the relation of several optimum r and R from numerical result, as shown in table 1.

Optimum r of table 1. and R

Optimum r (m)	1.2	1.6	2	2.4
					R(m)	4	5	6	7

The relational model of setting up optimum r and R is:

r＝aR+b (4)

Wherein: a, b are coefficient, and r representes that regional center arrives the distance of anchor node, and R representes zone radius.

In the last example, corresponding vector form is:

y＝Aθ(5)

Wherein, y=[r (4) r (5) r (6) r (7)] ^T, θ=[a b] ^T,

$A=\left[\begin{array}{cc}4& 1\\ 5& 1\\ 6& 1\\ 7& 1\end{array}\right]---\left(6\right)$

With numerical result substitution (4), utilize least square method can obtain θ:

θ＝(A ^T?A) ^-1A ^Ty＝[0.4 -0.4] ^T (7)

The relational expression that then requires is following:

r＝0.4R-0.4(8)

As can beappreciated from fig. 5, (8) are fine as to meet the relation of optimum r and R.

Technique effect of the present invention is: the anchor node that the present invention is based on the asynchronous location of ultra broadband is distributed method rationally; Clock is asynchronous between said a plurality of anchor node; The anchor node method of distributing rationally is: said a plurality of destination nodes to be measured evenly distribute, and said a plurality of anchor nodes are distributed on the summit of regular polygon, and said regional center satisfies apart from r to anchor node: r=aR+b; Wherein, a, b are coefficient.The anchor node that the present invention is based on the asynchronous location of ultra broadband is distributed method rationally, anchor node is arranged in optimal location can utilizes a spot of anchor node to obtain higher performance, thereby reach the compromise of performance and energy consumption; And if anchor node has been arranged in bad position, then can be cancelled the performance that the performance that a large amount of anchor nodes are obtained obtains not as a small amount of anchor node through increasing the performance gain that anchor node obtains.There is different optimum r in the zone of different sizes, provides the relation of the two.When considering path loss to the influencing of range error, there is an optimum r, if anchor node is arranged in this position, can obtain the average behavior of optimum.

Above content is to combine concrete preferred implementation to the further explain that the present invention did, and can not assert that practical implementation of the present invention is confined to these explanations.For the those of ordinary skill of technical field under the present invention, under the prerequisite that does not break away from the present invention's design, can also make some simple deduction or replace, all should be regarded as belonging to protection scope of the present invention.

Claims (5)

1. the anchor node based on the asynchronous location of ultra broadband is distributed method rationally, and clock is asynchronous between said a plurality of anchor nodes, it is characterized in that; The anchor node method of distributing rationally is: said a plurality of destination nodes to be measured evenly distribute; Said a plurality of anchor node is distributed on the summit of regular polygon, and satisfy apart from r to anchor node at the center of said destination node to be measured distributed areas: r=aR+b, wherein; A, b are coefficient, and R is the radius of destination node to be measured distributed areas.

2. distribute method rationally according to the said anchor node of claim 1, it is characterized in that, also comprise and consider the influence of path loss to range error, set path dissipation factor based on the asynchronous location of ultra broadband.

3. distribute method rationally according to the said anchor node of claim 1, it is characterized in that, also comprise and consider the influence of path loss, set the standard deviation of range error range error based on the asynchronous location of ultra broadband.

4. distribute method rationally according to the said anchor node of claim 1, it is characterized in that, comprise and obtain the average behavior that is evenly distributed on the destination node to be measured in the zone based on the asynchronous location of ultra broadband.

5. distribute method rationally according to the said anchor node of claim 1, it is characterized in that, adopt least square method that regional center is carried out mathematical modeling to anchor node apart from r based on the asynchronous location of ultra broadband.

Images